It is necessary in many orthopedic surgical procedures to employ a cement or grouting type agent, such as for attaching artificial joint implants, repairing or forming joints in bones, or other forms of orthopedic work. The type of cement generally used for these purposes is a self-curing resin formed from the blending of a wide variety of liquid monomers or comonomers with powdered polymers or copolymers to form a viscous admixture to be used as the grouting agent.
The admixture of the powder and liquid components develops a quick setting material. As such, preparation of the cement usually occurs directly within the operating area just prior to use. In particular, a bone cement mixing apparatus is generally utilized to mix the powder and liquid components in the operating area. The resultant admixture is then removed from the mixing apparatus and placed in a cement delivery apparatus for subsequent use by the surgeon. Specifically, the bone cement must generally first be scooped or otherwise removed from the mixing apparatus and thereafter placed in a syringe-type delivery apparatus for use by the surgeon.
The aforedescribed system for mixing and delivering bone cement has a number of drawbacks associated therewith. For example, monomer vapors are generated during the depositing of the monomer into the mixing apparatus and during the subsequent mixing of the monomer with the powder component of the bone cement. Such monomer vapors may be noxious and/or toxic. Because the bone cement is generally mixed in an operating room environment, it is important to prevent any monomer or its vapors from escaping the mixing apparatus. Because of this, some heretofore designed mixing apparatus have included mechanisms for controlling the escape of such vapors.
Such heretofore mixing apparatus can be categorized into three main mixing bowl systems. These three main mixing bowl systems are currently used in the industry. Once such mixing bowl is known as the Stryker mixing bowl. The Stryker mixing bowl utilizes a vacuum during the mixing process to remove fumes. The Stryker mixing bowl, however, has several deficiencies. Such deficiencies are that the mixing bowl is not clear so that the mix quality cannot be visualized, it has a fixed axis direct drive paddle that may allow for un-mixed powder to collect near the top of the bowl, and the lid does not lock into place. The direct drive paddle means that the user must manually reverse direction of the paddle to obtain the optimal mix quality of the cement. Further, the Stryker mixing bowl, while using a vacuum to remove monomer fumes during mixing, cannot remove the monomer fumes once the lid is removed.
Another type of mixing bowl is known as the Summit Prism mixing bowl. The Summit Prism mixing bowl has a gearing mechanism that creates a spirograph-type pattern within the cement being mixed. This action combined with the design of the paddle creates a folding motion of the cement which has been seen to mix cement fairly well. The paddle does not, however, reverse its direction. The paddle does, however, create a taffy pulling motion within the cement being mixed. The lid to the Summit Prism mixing bowl does lock, and the mixing bowl is clear to provide visualization of the mix quality of the cement. the Summit Prism mixing bowl, however, is not ergonomically designed and thus is hard to hold. Again, while using a vacuum to remove monomer fumes during mixing, the Summit Prism mixing bowl suffers from the same limitation as the Stryker mixing bowl in that there is no provision for removal of the monomer fumes once the lid is removed.
The third major system is the UltraMix mixing bowl made by DePuy Orthopaedics, Inc. of Warsaw, Ind. The UltraMix mixing bowl has an ergonomic sauce-pan type handle on the lid, the lid locks into place, and the blow interfaces with the DePuy Monomer Introducer also made by DePuy Orthopaedics, Inc. of Warsaw, Ind. The paddle of the UltraMix mixing bowl is a direct drive system, but is offset thus creating the folding motion within the cement being mixed that is advantageous. The direct drive paddle means that to obtain the optimal mix quality of the cement, the paddle needs to be reversed. As well, the speed of the paddle needs to be varied. Again, while using a vacuum to remove monomer fumes during mixing, the UltraMix mixing bowl suffers from the same limitation as the Stryker and Summit Prism mixing bowls, in that there is no provision for removal of the monomer fumes once the lid is removed.
In all heretofore systems, and not just the ones mentioned above, there is no means for actively removing monomer fumes once the mixing bowl lid is removed. Since such monomer fumes/vapors may be noxious and/or toxic, it is important to remove as much of the vapors as possible. With some cements, it is necessary to wait up to four minutes before the cement is ready for use.
Moreover, heretofore designed mixing apparatus have been plagued with problems relating to the incomplete mixing of the liquid component with the powder component. Specifically, the powder component and liquid component are often inadequately mixed during operation of heretofore designed systems.
What is therefore needed is an apparatus and/or method for mixing a bone cement that overcomes one or more of the above-mentioned drawbacks or inadequacies. What is particularly needed is an apparatus and/or method for mixing bone cement that reduces, if not eliminates, exposure to vapors form the liquid bone cement component within the operating area.